The Telecommunications Infrastructure has structure resulting from fundamental differences between its three component parts--the Access Infrastructure which provides connection to users, the Switching Infrastructure which provides dynamic handling of communication entities (e.g. "calls") and the Transport Infrastructure which interconnects geographically separated segments.
Telecommunications Networks are logical entities mapped onto the infrastructure, illustrated in FIG. 1. A Network can be of any size and may be "bent" into any shape but is limited by the infrastructure: in particular no discontinuities are permissible, which may be interpreted as meaning that the only acceptable topologies are those which will map retrospectively onto the existing infrastructure.
Aspects of a design for a segment of the access layer of an Asynchronous Transfer Mode (ATM) infrastructure conforming to the above definition are described.